This invention relates to gas turbine driven superchargers, commonly called turbo chargers, for internal combustion engines and is particularly well adapted for use on motor cycles.
It is well known in the prior art to increase the volume of an air induction charge in an internal combustion engine by providing a compressed air supply to the engine rather than induction directly from the atmosphere. Where the engine is provided with combustible fuel via a carburettor mixing the fuel with the induction air volume, the carburettor must include a petrol reservoir which supplies petrol to the carburettor jets. The petrol reservoir, or float bowl, is traditionally maintained at atmospheric pressure so that the carburettor may accurately proportion the fuel air mixture by virtue of the static pressure difference at the carburettor venturi compared with the fuel reservoir. For this reason carburettor supercharged (including turbo charger) induction systems traditionally placed the carburettor at the atmospheric end before the air compressor.
There have been proposals, such as U.S. Pat. Nos. 4760703 and 4822532 whereby for various reasons turbo charger compressors have been placed before the carburettor in the induction system. In U.S. Pat. No. 4760703 a large volume plenum chamber and adjacent air filter box with inter-connecting bypass valve connects directly to the carburettor intakes. A pair of air lines run to and from the air box and plenum chamber via the turbo compressor, the lines for the sake of efficiency being necessarily of large diameter and therefore on a motor cycle difficult to route without re-arranging other cycle components. U.S. Pat. No. 4822532 includes a turbo charger supplying pressured air to a specialised carburettor which has been developed specifically to overcome problems associated with excessive boost and would not usually be used on a naturally aspired engine.